New Taste in Music

The next day, Jon decided to listen to the radio while waiting for Karyn to come over and start wishing. This however, gave Jon an idea for a wish he could make before she got to his house. He then grabbed the rock and said "I wish all the girls in the world were transformed into stereotypical super _______ music fans." Just as he said it he say Karyn pull up in his driveway and could already see that she had changed. What genre did he pick?